1. Field of the Invention
The invention pertains to apparatus for processing and cleaning machine tool coolant fluids, and in particular, pertains to the separation of emulsified oil from the coolant fluid and, further, removing particles, bacteria and odors from the fluid.
2. Description of the Related Art
Machine tools utilizing cutters having sharp edges often employ a liquid coolant to cool the tool and work piece. Such coolant is usually pumped and sprayed upon the work piece at the point of contact by the machining tool. The machine tool coolant system normally including a pump supplied from a sump or reservoir associated with the machine tool, and upon the coolant being sprayed upon the cutting tool and work piece, the coolant normally falls to the sump and is recycled.
Machining operations produce chips, grit, and similar foreign matter particles which is continually recycled through the coolant system, and as the coolant may be alternately heated due to contact with a hot tool, and then cooled, and may set in a machine tool sump for extended periods of time without circulation, the coolant becomes contaminated with bacteria producing offensive odors, and such bacteria often becomes an irritant to machine tool operators causing rashes and various health problems.
While large coolant cleaning and processing equipment is known and available, such apparatus is expensive, and is normally only used by large machine tool shops which can afford the expensive coolant processing equipment along with the attendant complex conduit and circulation system required. Small machine tool operators do not have access to permanently installed coolant processing apparatus and, in the past, must periodically discard the contaminated coolant and replace the same with a new fluid, which is expensive, and such maintenance is often overlooked.
Apparatus available to small shop owners for processing and cleaning machine tool coolant fluids is shown in U.S. Pat. No. 4,772,402 of which the instant invention is an improvement. In U.S. Pat. No. 4,772,402, a coolant processing system is disclosed wherein coolant is pumped from a machine tool sump, coarse filtered to remove large chips and similar foreign matter, the pre-filtered coolant is then accumulated and under the control of a float sensor an electrically operated pump forces the pre-filtered coolant through a fine filter which includes activated charcoal which removes bacteria and many odors. After leaving the fine filter, the coolant is returned to the machine tool sump, and as the machine tool coolant is cycled and recycled through the processing apparatus, the coolant is increasingly cleaned and bacteria removed therefrom.
The treating of machine tool coolants by the processing and apparatus shown in U.S. Pat. No. 4,772,402 is suitable for removing chips and other hard foreign matter from the coolant fluid, and reducing bacterial count, but such apparatus is not capable of separating emulsified oil and other light contaminants from the coolant fluid, and in fact, due to the mixing action of the pumps of this patented device, coolant fluid of higher density is intermixed with emulsified oils of lower density, and the deleterious effect of emulsified oil within coolant fluids is magnified and propagated by the apparatus of U.S. Pat. No. 4,772,402.
Undesirable oils, such as emulsified oils, have a lower density than that of the normal coolant and adversely affect the efficiency of the normal coolant fluids. Such emulsified oils may occur from coatings previously applied to the work piece being machined, or may result from a breakdown of the components of the cooling fluid over a period of time due to the exposure of high temperatures at the point of machining. Emulsified oils multiply bacterial growth and odor problems, and are a primary reason for the need to periodically replace coolant fluids. Previously, coolant processing apparatus available to small machine tool operators capable of removing emulsified oils has not been available.